So, clearly 'setuid 1000' is not valid and hence neither is your job. Attempting to start a job manually which specifies 'setuid 1000' fails with the error:
start: Job failed to start
I have so far been unable to recreate your hang. Please specify which versions of Ubuntu are being used inside and outside the container.
man(5) shows the syntax for the setuid stanza as:
setuid USERNAME
So, clearly 'setuid 1000' is not valid and hence neither is your job. Attempting to start a job manually which specifies 'setuid 1000' fails with the error:
start: Job failed to start
I have so far been unable to recreate your hang. Please specify which versions of Ubuntu are being used inside and outside the container.